It's very unfortunate you have had this experience. Of course, we all know things can and will break, but the owner should have made a sincere effort to fix the dishwasher and look into the wifi issue. We feel you are being very reasonable in asking for a 10% refund. Our spa has had problems in the past and we have given a discount like this when we couldn't make it right for more than half a week's rental and also sincerely apologized for the inconvenience. You should have heard from the owner, especially as the contract has a clause that they will address problems.
We don't know that VRBO can help you, but it's worth a try to contact them. And try the owner again too. Good luck.
I do not think that VRBO will do anything. The only thing that they could do would be to remove the listing from their website and I doubt very much that they would do that. I do not think that VRBO acts as an ombudsman between owners/property managers and guests.
How long ago did you e-mail the owner? It is possible that he is out-of-town or his e-mail is down. You might consider e-mailing again or telephoning him.
How long has it been since the rental ended? Does the contract state the timeframe in which the owner will refund your security deposit? Many states have laws that require the owner to refund the deposit or explain why some or all of it is being withheld. I know that under Maine law, this must be done within 30 days of the date the rental ended.
Hopefully, the owner will respond promptly to your concerns, which I believe are quite legitimate. I don't know what would be reasonable compensation for not having a working dishwasher and wifi as advertised, but I think that it would be wise of the owner to want to have you as a satisfied customer.